By pure chance I'd written down the wrong map ref for this (not the first time) and looked in completely the wrong place (a common nuisance). Still this proved fortunate as the farmer appeared in his tractor as I was climbing the fence half way up the Knock Of Formal and promptly said that the stone was next to my car.
The stone is now gradually getting covered in moss and grass. It might possibly be forgotten about altogether. Still the farmer has other ideas and wants to re-erect the stone at some point. So HS have been emailed with all the contact stuff so fingers crossed that they pull the finger out.
It is a nice shaped stone being over two meters in length and is a meter wide. Couldn't see any markings once I'd cleaned the snow away. Hopefully the next time I come here it might maybe be standing.